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Medical xrayThursday 2 February 2012 3:47pm

Virology form. New University of Otago research suggests that 6.5% of gay and bisexual men in Auckland have HIV, with a fifth (21%) of these unaware of their infection.

This is the first time a biological measure of HIV has been collected in community settings among this population, providing an estimate of the amount of undiagnosed as well as overall HIV infection. The study is timely, because in 2010 the highest number of new HIV diagnoses was recorded among gay and bisexual men in New Zealand indicating that it remains a major health issue in this population.

“The existence of people with undiagnosed HIV infection must be taken seriously if we're to bring HIV under better control,” says lead investigator Dr Peter Saxton of the Department of Preventive and Social Medicine, University of Otago.

“Overall about 1 in every 80 gay and bisexual men in this 2011 Auckland study had undiagnosed HIV infection. A person with undiagnosed HIV cannot tell someone they're infected and might not initiate safe sex. The practical reality of this is that everyone, especially gay men, needs to become better educated, supported and proficient at safe sex to control HIV and other sexually transmitted infections.”

“While HIV testing is a cornerstone of control and needs to be made more accessible, increasing testing alone is not the answer,” says Dr Saxton. “There will always be a lag between infection and diagnosis, and a person is particularly infectious early in the course of HIV infection when partners can be exposed unwittingly. This is why condom use remains key to control of your own and your partner's risk”.

He adds: “Individuals with HIV who remain undiagnosed delay treatments that can improve their quality of life and life expectancy. While treatments don't eliminate the HIV virus, they keep it at low levels and also reduce a person's infectiousness to others.”

The February 2011 study recruited 1049 gay and bisexual men from community settings. Participants were invited to complete an anonymous questionnaire and provide an anonymous saliva specimen, which could be linked together by a unique code. By comparing respondents' self-reported HIV test history with their saliva result, researchers found that 14 of the 67 HIV positive men did not know they were infected, or 1.3% of all respondents. Most of these men believed they did not have HIV, and many had previously tested for HIV.

There were no differences in overall HIV infection between European and Maori participants. However, HIV infected non-European respondents were less likely to be aware they had HIV. Younger infected gay men also appeared to be less likely to be aware of their infection.

“New Zealand has one of the best records of HIV control internationally,” says Dr Saxton, “and we need to keep it that way by encouraging condom use and earlier diagnosis among those most at risk”.

The study findings are available free online from the journal BMC Public Health.

Saxton P, Dickson, N, Griffiths R, Hughes A, Rowden J. Actual and undiagnosed HIV prevalence in a community sample of men who have sex with men in Auckland, New Zealand. BMC Public Health 2012.

The study was conducted by researchers at the AIDS Epidemiology Group, Department of Preventive and Social Medicine, University of Otago, in collaboration with the New Zealand AIDS Foundation. It received ethics approval from the Northern X Regional Ethics Committee and was funded by the Health Research Council.

For more information, please contact

Dr Peter Saxton
Postdoctoral Research Fellow, AIDS Epidemiology Group
Department of Preventive and Social Medicine (Auckland based)
Dunedin School of Medicine
University of Otago
Tel +64 9 373 9725

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